Helical resistor



Feb. 20, 1951 H. BOWlTZ ETAL HELICAL RESISTOR Filed Feb. 18, 1949 i W 6.A 6 Mn m m O 1% AM /WM)".

A APMA 50/4072, 5744 15/53 WWI/10M,

' 4rrmw Patented Feb. 20, 1951 HELICAL RESISTOR Harlan Bowitz, LosAngeles, and Stanley S. Fishfader, Wilmington, Calif.

Application February 18, 1949, Serial No. 77,136

2 Claims.

This invention relates to a helical resistor and the object of ourinvention is to provide a resistor of helical shape, in which there is agreater length of windings on the resistor body than in devicesheretofore devised.

Another object of our invention is to provide a device of the characterstated, which is simple in construction, easy to assemble, and which iseffective to vary resistance over a wide range.

A feature of our invention is to provide a novel helical resistor inWhich the terminal contacts are simply attached and are effective in themanner in which the contact is made.

Other objects, advantages and features of invention may appear from theaccompanying drawing, the subjoined detailed description and theappended claims.

In the drawing:

Figure 1 is a rear elevation of our resistor with only a portion of thewindings shown in position.

Figure 2 is a sectional view taken on line 2--2 of Figure 1.

Figure 3 is a fragmentary sectional view taken on line 33 of Figure 1.

Figure 4 isran elevation taken in direction of line 4-4 of Figure 3.

Figure 5 is a sectional view taken on line 5-5 of Figure 1.

Figure 6 is an elevation taken in direction of line 6-6 of Figure 5.

Our helical resistor A is mounted on the rear face of a panel 4 andextends at right angle to this panel. A shaft II is rotatably mounted inthe resistor A and extends through the panel 4 and this shaft is rotatedby means of a knob 2, which is secured to the shaft by the set screw l.A tube l2, formed of insulating material, is fixedly mounted in thepanel 4 by means of the nuts 3 and 5, which are threaded on the tube andbear against the front and rear faces of the panel 4, respectively. Theshaft H extends through the tube l2 and is journalled therein.

The helical or spiral body 1, which is also formed of an insulatingmaterial, such as porcelain, or the like, is fixedly mounted on the tube12, in that the tube fits within the center of the body I and the nutalso bears against the bottom of the body, thus holding it in position.

For the purpose of this explanation, the dimension extending at rightangles to the panel 4 will be called the width of the spiral body 1. Thewire windings 8 are wound over the width of the body 1 and thesewindings are continuous from the outside to the inside of the spiralbody.

With this arrangement, it is possible to mount a great length of wire onthe spiral body and still maintains the horizontal and verticaldimension of the resistor within reasonable limits.

A contact arm I9 is mounted on the inner end of the shaft H and theouter end of this contact arm is curved, as shown at It to fit thecurved upper contour of the windings 8. The inner stop and wire terminal[3 consists of a clip which 2 extends over the width of the body 1 andis bolted to this body by means of the bolt [4 and the nut I5 threadedon this bolt. This acts as a stop for the arm l0 and also serves to actas a terminal binding post for the windings 8.

A similar terminal clip 16 is mounted at the outer end of the spiralbody 1 and this clip is attached to the body by means of the bolt I1 andthe nut l8 threaded thereon. The arm H! is slidably mounted on the shaftII by means of the slot l9 formed in the arm, the shaft having a groovetherein to enter the slot [9. Thus, the arm I 0 can slide laterally withrelation to the shaft II as the arm is rotated and as it follows thehelical path of the body I.

The terminal mounts l3 and I6 also act as binding posts for the wirewindings 8. The terminal connected to the arm It consists of a metalstrip 6, which is positioned under the arm [0 and is thus in contactwith said arm, the other end of said strip extending downwardly andbeing bent over the face of the body 1 adjacent the panel 4. A lead tothis strip is thus separated from the arm [0 and does not interferetherewith.

Having described our invention, we claim:

1. A helical resistor comprising a helical body, wire windings wound onthe body and over the width of said body, mounting means on said bodywhereby the body may be attached to a panel, a shaft journalled in thebody, an arm mounted for lateral movement on said shaft, the outer endof said arm being curved to fit the windings and a knob attached to oneend of said shaft, a terminal clip, one end of which is positioned undersaid arm and surroundin said shaft, the other end of said clipprojecting from said body on the side opposite said arm.

2. A helical resistor comprising a helical body, wire windings Wound 0nthe body and over the width of said body, mounting means on said bodywhereby the body may be attached to a panel, a shaft journalled in thebody, an arm mounted for lateral movement on said shaft, the outer endof said arm being curved to fit the windings, and a knob attached tooneend of said shaft, a terminal clip, one end of which is positionedunder said arm and surrounding said shaft, the other end of said clipprojecting from said body on the side opposite said arm, an inner and anouter clip mounted on said body, said winding being attached to each ofsaid clips, said clips acting as inner and outer terminal stops.

HARLAN BOWITZ. STANLEY S. FISHFADER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,450,919 Harris Apr. 10, 19232,429,592 Beagles Oct. 28, 1947

